I cannot believe that people actually see sense in the positive discrimination policy.
Suppose a child is from a bad state school and one is from a the best state school in the country. Then should oxbridge discriminate against the second one? NO. Oxbridge are there to nurture the best talent, no matter where it is produced. If most states schools do not stretch their students enough, then most private schools will. At the end of the day, most private schooled children will be better suited to an Oxbridge education than state schooled students.
It may be unfortunate that entry into private education is largely dependent on wealth, but clearly students who go to these institutions, and their parents, are not to blame. Blame the game, not the player. The 'game' can be made fairer if grammar schools are reinstated and if they give an education on par with private schools, but on the state's pay. Alternatively, more students should apply for bursary places at top private schools. Both these options will lead to the best minds being in the best schools (i.e. brilliant grammar schools o rprivate schools) and then the best minds from the best schools proceeding to the best unis.
But clearly it is too costly and time consuming to make sure the grammar schools pull up their socks and that all the best students are diverted to these institutions. Its much quicker and cheaper (but wronger) to tell Oxbridge to discriminate against privately educated students.